Appliance Operation - Potterton Promax SL Series Installation & Service Instructions Manual

5. Air Box
6. Fan Protection Thermostat
7. Fan Assembly
8. Condensate Trap
9. PCB Housing Assembly
10. Gas Tap
11. Gas / Air Ratio Valve
12. Flow Pipe Connection
13. Return Pipe Connection
14. Flow Temperature Safety Thermostat ­ Black
15. Flow Temperature Thermistor ­ Red
16. Flow Switch (dry fire protection)
page 8
3.0 Appliance Operation
3.1
1. Switched Live On: When the switched live switches on if the flow temperature is less than the set point then pump overrun
occurs. When the switched live switches on if the flow temperature is greater than the set point then pump overrun occurs.
2. Pump On: The pump is on while the fan, spark generator and gas valve are off. After 10 seconds if the flow switch has made
then fan pre­purge occurs. After 10 seconds if the flow switch has not made then anticycle occurs.
3. Fan Pre­Purge: The pump and fan are on while the spark generator and gas valve are off. After 5 seconds ignition occurs.
4. Ignition: The pump, fan, spark generator and gas valve are on. If a flame is detected then burner on occurs. If a flame is not
detected within 5 seconds and less than 5 ignition attempts have been made then fan purge occurs. If a flame is not detected
within 5 seconds and 5 ignition attempts have been made then ignition lockout occurs.
5. Burner On: The pump, fan and gas valve are on while the spark generator is off. Flow temperature is controlled by varying the
fan speed (and thereby the gas rate) to achieve optimum operation. If the flow temperature is greater than the set point or the
TRVs all shut down then fan post purge occurs.
6. Fan Post Purge: The pump and fan are on while the spark generator and gas valve are off. After 5 seconds if the TRVs are not
shut down then pump overrun occurs. After 5 seconds if the TRVs are shut down then anti­cycle occurs.
7. Pump Overrun: The pump is on while the fan, spark generator and gas valve are off. After 1 minute anticycle occurs.
8. Anti­cycle: The pump, fan, spark generator and gas valve are off. After 3 minutes if the flow temperature is less than the set
point then pump on occurs. After 3 minutes if the flow temperature is greater than the set point then pump overrun occurs.
9. Ignition Lockout: The pump, fan, spark generator and gas valve are off. The boiler can only be reset by manually using the reset
button.